开云体育

All:

I was sending out order notices from people who had written me about the board and sending the response to the group instead of the individual. (A lot of people placed orders, but did tell me where to ship the board(s).) I'll try to pay closer attention down the road.

Jack, W8TEE

Use a website like websdr.org to tune into a strong broadcast, and then try to find that same broadcast on your bitx.

Of course, this assumes the SDR station is showing the correct frequency.

Alternatively, if you do make contact with someone who has a more precise rig, ask them what their exact frequency, then use that information to calibrate.
--
Darren, W9ZIM

Terry,

Here's another trick:
in the evenings there are quite a few strong broadcast stations in the
section above 7200 kHz. You should be able to hear them even when you live
"in the sticks".
As these are broadcasting an AM signal with unsuppressed carrier you can
use them for calibration your radio.
Broadcast stations are usually precisely on frequency at 10 kHz intervals.
You will hear a strong whistle when you tune to a broadcast station. As
you tune trough the signal, the pitch of the whistle will go from high to
low until it is zero and then go up again.
The point where the whistle is exactly zero Hz is "zero beat". You can use
this as a reference point for calibrating your radio. In calibration mode,
adjust the offset value so that the whistle is zero Hz.

73 Allard PE1NWL

Hi Allard,

It was very clear tone. I will check again and inform you

73 Yiannis, SV5FRI

I hear you loud and clear. Even if it's not a 0 or 5.
Ken,T

hi allard

the problem that i have had with calibration is finding a carrier on an exact frequency

i live in the sticks so finding a local station is hard to come by

73 de terry gm4dso

Thanks for feedback Yiannis,

yes apparently 47K is too high a value in some cases.
Perhaps 10K is a safer value so that it works in all cases.

How is the generated CW carrier? Is it still a clean CW signal with no
clicks?

73 Allard PE1NWL

Hi

I have faced the same problem with the CW modification and I replaced the resistore 47K with 10K and output power is 5,5 watt on CW

Yiannis, SV5FRI

True for normal SSB operation.
But it can be fixed easily so why not.

For certain digital modes exact frequency display may be crucial.

73 Allard PE1NWL

Joe , that is a good point about bleeding the caps down not that they are a high value .
I have been looking at other circuits where the LM386 is involved and they all ( except BITX40)
have from pin 5 of LM386?? Cap ( c112) first then 10 Ohm (r110) to ground ?????

hi
does it actually matter that your frequency display is slightly off. As long as you are transmitting and receiving on the same frequency as you contact station then all is well.

terry gm4dso

Yes that't the right connector, short the red wire to ground to go into
calibration mode.

Alternatively, if you install the latest raduino sketch, you can do the
calibration from the front panel via the Function Button menu. Then you
won't need the red wire anymore.

73 Allard PE1WNL

You should get near 1.5A current draw when transmitting a loud "Hello". You may have to set the IRF510 bias again.?
Are you measuring the current draw in the power lesad that goes to the IRF510??

Note that there are 2 places where you need to supply 12v to the rig. 1 powers everything except the final and the other powers just the final (IRF510).
This allows you to get more power out by supplying the final at higher voltage. I have used up to 28v on mine to get about 25 watts out.

--
Mike VK3XL

In the good old days before digital readouts on radios transmitting on 7.222 MHz would not get a comment, now if your frequency dos'nt end in a 0 or a 5 you are accused of being off frequency.... maybe we should throw out our vfo rigs and go back to crystal control.....?
--
Mike VK3XL

And now it's finished:



A bit messier inside than I intended, but this is my first project like this where I had to fabricate the case and figure out all the point-to-point wiring on my own.? Still, it works, so I'm pretty excited.? The speaker is from an old clock radio that I picked up today for a few dollars.? I wired everything up to the jack following the directions helpfully provided by John Smith, and the speaker works, but when I went to plug in my headphones, the plug refused to go in.? Either I damaged the socket when soldering, or, more likely, a bit of the glue I used to affix the socket in place accidentally got inside and fouled up the inner workings. :(

Oh well... maybe I'll fix it in the future... or not.

Assembled the microphone and ran a few tests into a dummy load.? All the amperage readings were as expected, which made me happy.? Measuring voltage on the dummy load, it looks like I'm outputting around 4 to 5 watts.? Not the 7-watts advertised on the hfsigs page, but not too bad, either.



I strung a 40 meter end-fed dipole from the kitchen and across the living room to see if I could hear anything, and to my delight, I could!? The receiver is rather noisy with a bit of buzz which I suspect is coming from my power supply which I salvaged from a junk PC at work and turned into a stand-along unit.? I've read that these can be noisy beasts, so I'll need to figure out how to filter it to get the buzzing out of the audio.

In the image above, you can see my laptop running websdr.org.? I found an SDR station relatively near me and tuned it into a strong signal.? Then I found the same broadcast on my bitx and used that to align receiver.

And then I accidentally broke the delicate microphone push-button that's supplied with the kit, so back to square one with there.? I still have a bit more work ahead of me before I can finally get on the air, but it's coming along, and I'm having fun.
--
Darren, W9ZIM